Flexible endoscopes are axially elongate instruments that are navigable through natural body lumens of a patient for remotely evaluating and/or treating a variety of ailments. Endoscopes have viewing capability provided by fiber optic elements that transmit images along their length to the medical care provider. Endoscopes may be specifically configured in length, diameter, flexibility and lumen configuration to navigate to specific treatment areas in the body and conduct specific procedures. Such a specifically configured endoscope may be known by a specific or functional name, for example as a laparoscope, duodenoscope, colonoscope, sigmoidoscope, bronchoscope or urethroscope.
In combination with remote viewing capability, endoscopes are frequently configured to provide a working channel through which shaft mounted tools and medical instruments may be navigated and remotely operated. More recently, flexible endoscopes have also been used to deliver devices, medications or coatings to internal sites.
The outer diameter of flexible endoscopes varies depending on style and intended function. For example, a flexible endoscope typically used in gastric procedures, having a single instrument channel, can have a nominal diameter ranging from under 10 mm to over 12 mm (e.g., the Olympus XGIF-Q160Y9 single channel endoscope), while a dual instrument channel endoscope may range in diameter from under 12 mm to 15 mm or larger, (e.g. the Olympus GIF2T160). There is no absolute gauge or completely standard set of sizes in the industry at present. The particular endoscope for a given procedure is selected by the physician, and may vary depending on procedure and cost related factors. Hence, the geometric size of an instrument which may be used in a specific procedure is generally impossible to predict.
Moreover, endoscopes are typically constructed of wall-forming parts that are interconnecting but flexible, and a fluid-impermeable coating, typically of plastic reinforced with fabric. The resulting instruments are complex and expensive, and so they are normally re-used, after cleaning and sterilization. These procedures can alter the diameter, and especially the shape, of the instrument in general and especially of the distal tip zone, which is the area of highest articulation and wear.
To accommodate multiple functions within a single instrument construct, there are typically a number of different discrete functional elements bundled within the instrument. Such elements of a typical flexible endoscopic instrument include visualization systems, such as an optical fiber light source and a fiber bundle visualization system with a terminal lens; one or two passages for other functions, such as drug delivery or tissue manipulation; insufflation channels for injecting air or gasses into the body cavity; multiple control wires for distal tip articulation; and fluid channels to direct fluid across the visual imaging lens to remove to flush debrief or tissue which may occlude it. Endoscopic design is very configuration specific, for in order to accommodate these multiple functions in an articulating tip, an endoscope will typically need to have these features arrayed in a pattern which can be best visualized and understood by thinking of the endoscope as being composed of a number of wedges, like a sliced pizza, each with a different function, flowing axially.
As a result, most current endoscopes have their viewing optics, and often their illuminating optics, in an off-center location. Often, no one feature of a multifunctional flexible endoscopic instrument is located on the direct central axis of the instrument. In fact, it may be advantageous to not have any feature aligned with the instrument centerline of the distal tip feature, to allow stabilizing the device with a tension wire secured at the axis centerline to the distal end of the articulating portion. This feature location method is one effective way to apply a tension to lock together the various nesting or articulating elements of the endoscope, while still allowing multiple degrees of freedom to move a discrete distal portion of the device by use of control wires located in an axial array running along the outer circumference of the instrument. This layout of features is well known and documented in endoscope designs. In particular, as documented in many endoscopic products with off axis optics, and as generally represented by the Olympus XGIF-Q160Y9 and Olympus GIF2T160 instruments, an imaging lens at the distal tip of the flexible endoscopic instrument will usually not be positioned on the center axis of the instrument itself but rather located at an offset position with respect to the centerline of the instrument.
These geometries require adaptations to perform other functions of the endoscope, and in particular favor mounting components on the outside of the endoscope tip. For example, U.S. Pat. No. 7,204,804 to Zirps et al. describes a mounting adapter for releaseably securing accessories, tools, or medical instruments to the distal end of an endoscope. The adapter is most compatible with endoscopic accessories that have a cylindrical mounting surface, and is positioned over a length of the distal end of an endoscope. The Zirps et al adaptor is provided in two components to support both ends of a cylindrical accessory on the endoscope surface. This adapter holds the accessory on the endoscope shaft by frictional engagement, and is configured to maintain the accessory concentric with the shaft along its length. The adapter also is configured to mount an accessory on a wide range of commercially available endoscopes, and to do this, it requires a number of different and distinct sizes of adaptor, typically provided together in a kit, to cover a wide range of instrument size and variation. Even with multiple sizes of insert, the actual diameter adaptability has a narrow range—for example, a range of from 10 to 11.3 mm, with three different diameters of adapter, is cited.
This particular adapter is ideally most suited to securing an attachment to a smooth, cylindrically concentric endoscopic instrument (such as a rigid laparoscope with an imaging lens located centrally), because it uses a series of multiple compressing fingers radially emanating from an axially located and axially centered ring feature, and is secured by a second closed perimeter concentric locking collar. Such mechanisms are known in the art, and as commonly used in the machine tool industry are known as “collets”. The holding system presented in the No. 7,204,804 Zirps et al patent is a collet type of holding system and is described in Wikipedia and other Machine Tool and Woodworking descriptive glossaries as follows:                “A collet is a holding device—specifically, a subtype of chuck—that forms a collar around the object to be held and exerts a strong clamping force on the object when it is tightened via a tapered outer collar. It may be used to hold a work piece or a tool. Generally, a collet chuck, considered as a unit, consists of a tapered receiving sleeve (often integral with the machine spindle), the collet proper (usually made of spring steel), which is inserted into the receiving sleeve, and (often) a cap that screws over the collet, clamping it via another taper.”        
Collet based systems require, by their design and function, the geometrical property that the centerline axes of “the machine spindle”, “the collar around the object”, “the outer collar” and “a work piece or a tool” as described in the above definition be co-axial. The use of a collet design requires that the article or tool grasping system typically be comprised of at least two or more finger-like entities arrayed as an even number of axial symmetric finger-like entities placed as matching pairs or an odd number of symmetric shaped finger like entities, evenly radially arrayed about a diameter which are then diametrically compressed in unison by a second cylindrical embodiment moving (slideably) in an axial direction to engage the article to be secured which in this art is an endoscope. Such uniform radial compressions systems using multiple finger-like gripping features are highly advantageous where the concentric, coaxial alignment of the engaging system and the article to be secured must be maintained (such as high speed spinning of a cutting tool in a hand drill or machine tool spindle for example). Similar features and attributes as described by No. 7,204,804 Zirps et al are used to align the axis of the article to be secured (the device attached to the ‘collet’ system of Zirps) with the central axis of the positioning instrument (the endoscope) thus providing coaxial positioning.
For the purposes of this application the geometric definition of a cylinder from the Encyclopedia Britannica is hereby cited (http://www.britannica.com/EBchecked/topic/148295/cylinder).
“In geometry, a surface of revolution that is traced by a straight line (the generatrix) that always moves parallel to itself or some fixed line or direction (the axis). The path, to be definite, is directed along a curve (the directrix), along which the line always glides. In a right circular cylinder, the directrix is a circle. The axis of this cylinder is a line through the centre of the circle, the line being perpendicular to the plane of the circle. In an oblique circular cylinder, the angle that the axis makes with the circle is other than 90°. The directrix of a cylinder need not be a circle, and if the cylinder is right, planes parallel to the plane of the directrix that intersect the cylinder produce intersections that take the shape of the directrix. For such a plane, if the directrix is an ellipse, the intersection is an ellipse. The generatrix of a cylinder is assumed to be infinite in length; the cylinder so generated, therefore, extends infinitely in both directions of its axis. A finite cylinder has a finite base, the surface enclosed by the directrix, and a finite length of generatrix, called an element.”
A number of tissue-closing devices in the current art describe mounting and securing techniques for positioning of a securing device on an endoscope. Such embodiments typically use cap-like distal mounts and elastomeric securing rings. Examples include U.S. Pat. Nos. 5,320,630 and 5,462,559 to Ahmed, U.S. Pat. No. 5,697,940 to Chu et al., U.S. Pat. No. 5,853,416 to Tolkoff, U.S. Pat. No. 6,974,466 to Ahmed et al, U.S. Pat. No. 7,214,231 to Tolkoff and U.S. Pat. No. 7,189,247 Zirps et. al. These patents describe a class of ligator band products currently in the marketplace. These references also describe the design and application of various endoscope-based or endoscope-mounted delivery systems and means for securing them to the end of an endoscope. These delivery systems are used to locate and place a tissue-closing embodiment during a surgical procedure, and typically comprise an elastic annular loop or ring feature which grips the endoscopic instrument's outer diameter circumferentially at a location near its distal end, with the ring-like loop being coupled to a rigid cap-like member located distally of the endoscopic instrument distal end. These embodiments are mounted sealably on the endoscope tip, and held in place by the radial compressive force of the elastic member on the instrument gripping the endoscopic instrument with a uniform compressive force and providing general coaxial alignment. Such designs are well known in the art and typically create a central chamber distal to the endoscope tip inside the cap, such that vacuum energy applied through an instrument channel can draw tissue into the central chamber for the mounted device to secure.
Another type of tissue closing embodiment is exemplified by a serpentine closure device which is carried on the outside of the distal tip of a delivery tube (which may be an endoscope), and which is deployed by pushing the device off of the end of the tube. This type of tissue closing device delivered on the end of an endoscope is described by US patents to Durgin et al, including U.S. Pat. No. 6,428,548, U.S. Pat. No. 6,849,078, U.S. Pat. No. 7,211,101, U.S. Pat. No. 7,001,398 and US 2006/0135989. The placement device used in positioning this embodiment also has a cap mounted on the external end of the endoscopic instrument, functioning essentially as described above in band ligation technology.
Another type of device and its delivery are described in commonly-owned pending applications US 2007/0225762 and US 2007/0270752. These applications describe a tissue closure device comprising a superelastic torsion ring with stabilizing and tissue-piercing projections, which can be carried either on the inside or outside of an endoscope or tubular member, and a device for facilitating its delivery. Positioning on the inside of an endoscope distal end or introducer tube is preferred, and is advantageous to prevent interaction of the closure device with tissue during transport, site location and manipulation.
Figures and descriptions within the present application describe the integration of the commonly-owned pending application tissue closing device into the present invention with a specific and unique geometry to enable effective safe and secure delivery of tissue closing fasteners by an endoscopic instrument.
All described prior art embodiments known including the above described commonly-owned pending applications US 2007/0225762 and US 2007/0270752 and co-pending U.S. application No. 61/199,606 have followed the basic design principle of using a flexible, closed perimeter, generally cylindrical adapter to align concentric and co-axial the delivery device or attachment device center axis with the endoscopic instrument center axis, and then, in some cases, applying a component for providing some form of direct or indirect radial compression forces to effect a vacuum seal and a secure the device position. Such devices are portrayed as having a closed perimeter, i.e. a hollow cylinder forming by a complete circle. This art further describes a sealable chamber created by the coupling of the distal device carrier to the endoscopic instrument, which is located distal to the endoscopes' most distal feature, such that vacuum energy can be applied to draw tissue into the defined chamber. Alternatively, graspers or any type of tissue manipulation means may be employed to draw tissue in said chamber to effect a closure
All of the instruments used in the above-cited art for locating and positioning the described devices can be described as “endoscopic instruments”, and in this application, the word “endoscope” or “endoscopic” will refer to the entire class of endoscopic and laparoscopic instruments, including other surgical instruments intended to be used to remotely manipulate tissue in a surgical procedure, unless stated otherwise.
While it is feasible to design an externally-mounted device for a particular endoscope in its original condition, for example a 10 mm endoscope, it can be very difficult to use such a system on endoscopes which have repeatedly been resterilized or repaired. The distal end of such endoscopes can become somewhat non-circular with use, and the fabric-based outer sheath can loosen. As a result, it is hard to get an externally-mounted device to slide onto a used endoscope, and yet remain in a tightly locked state during the conduct of a medical procedure. Elastic mountings that are tight enough for new endoscopes may not fit onto old endoscopes, while mountings that will fit can be too loose for stable positioning during procedures. Even with an appropriate diameter, the externally-mounted device may rock or tilt when being inserted or removed, and there is a risk of detachment of the device from the endoscope while in the body. While in principle a dedicated endoscopic instrument or a unique sized device can be provided for every endoscopic procedure and significant variant thereof, in practice this is a significant increase in expense in an already expensive field, and is not a preferred solution to the problem of fit and security.
Moreover, a coaxial “collet” type of system, as described by U.S. Pat. No. 7,204,804 Zirps et al., is not very adaptable, and requires a number of exchangeable parts to be tried before a particular endoscope can be used with a particular adapter. This is not a desirable situation during surgery. The coaxial “collet” systems represented by U.S. Pat. No. 7,204,804 Zirps et al., while an improvement in instrument grip over a pure elastic ring or similar embodiment, for example as represented by U.S. Pat. Nos. 5,320,630 and 5,462,559 to Ahmed, still are limiting in that the range of locking variability of the “collet” device is limited by the amount of radial compression the locking collar can attain on the collet “fingers” over a fixed axial length of travel.
The prior art embodiments are also further limiting in their effect on the visual field of view once mounted. As described above, the visual lens is typically not centered on the centerline of the endoscopic instrument. Such off axis lens placement, combined with a cap on the instrument projecting more distal to the instrument distal tip, creates a limiting effect called “tunnel vision”, due to looking through a tube where the walls constrict the field of view to a narrow central aperture. U.S. Pat. No. 7,189,247 Zirps et. al. has attempted to address this field of view problem by providing an extendable and retractable feature holding devices to be deployed. It is still utilizing the basic endoscopic instrument coaxial “collet” or elastic boot mounting principles previously discussed.
U.S. Pat. No. 7,189,247 Zirps et. al. clearly describes a portion of the delivery system which has operator controlled axial movement. The practice of operating the extending mechanism to create space that allows tissue to be drawn into a chamber for fastener attachment can lead to some confusion by the operator as instrument position of the distal tip (device length) along with field of view and focal distance of the optical system is changing device during actuation. This mechanism requires operator interaction and activation for proper function and result. When space within the body cavity is limited such extension movement needed may not execute fully or may cause trauma or inadvertent loss of distal tip location. As such, the requirement for movement of the instrument distal tip thus changing the working length when in the body cavity to generate a “tissue cavity” as a required by U.S. Pat. No. 7,189,247 Zirps et. al. is therefore a distinct disadvantage.
There is a need for visualization to be improved with endoscopes carrying adapters. There is a need for a reduction in the complexity and time of mounting tissue closure devices to endoscopic instruments. There is a need for any endoscopic mounted device to be positioned and locked quickly, easily and securely to the distal tip of the endoscope regardless of instrument size, and there is a further need for such an endoscopic mounted device to hold firmly and ensure a fixed instrument axial working length.
Endoscopes are purposefully designed with an extremely wide angle lens to provide the clinician with as much view of the tissue and surrounding environs as possible. In the delivery of bands, clips and the like, in order to provide that wide view, the endoscopic instrument should in principle be located distally and matched to the device distal tip. In practice this is not usually feasible, because with many closure devices described in the art, tissue needs to be drawn into a center zone of the deployment housing, to where the endoscope is located, to provide an effective closure. As a generalized well known procedure technique with a successful history of application and therapeutic result, it is a preferred clinical method. Therefore, the endoscopic instrument must be positioned some distance proximal to the overall distal tip of the delivery device when actively engaging tissue for the purpose of effecting tissue manipulation or closure and therefore in that configuration or use the endoscope has a limited field of view.
The preferred embodiment of the invention is designed to meet the expressed need for improved field of visualization, reliability ease of use and reduced complexity, adaptability to wide range of endoscopic instruments as compared with current art. The novel features and functionality of the invention include several improvements over the art.
One aspect of the invention is to provide improved mounting means, to allow more flexible pairing of particular endoscopes or endoscopic instruments with devices to be carried on their exteriors, while maintaining a tightly locked position of the external device on the instrument.
In another aspect, the invention provides the ability to mount such devices onto instruments where the distal portions of the instrument may have a highly variable geometry within the mounting area. Such geometry may include highly conical features, convolutions, or tapered configurations on the endoscope, therefore requiring such an adapting capability to sufficiently engage the instrument.
In another aspect, the invention provides the ability of the mounting device itself to easily adapt to a wide range of endoscopic instruments using a single universal mounting system, thus providing the clinician with the capability of changing an endoscopic instrument size within a procedure without needing to have multiple matching adapters to mount on such instruments.
In another aspect, the invention provides a clinician with an improved wide angle viewing capability in order to attain true peripheral visualization capability even after the mounting of an adapter onto the endoscopic instrument.
In another aspect, the adapter is diametrically flexible and compliant yet axially rigid, and thereby can engage a wide range of instruments and instrument shapes. The invention further provides mechanisms, geometric relations, and securing systems to allow a lateral offset of the axis of the adapter from the axis of the endoscope. This may be accomplished by the use of features, singly or in combination, selected without limitation from device stops, non-symmetrical geometries, non-closed cross-section geometrical constructs, isotropic and non isotropic materials configured into non-isotropic geometrical shapes, and combinations of closed and non closed perimeter feature geometry.
The geometric properties and flexible fitting capability of the adapter enables a wide range of endoscopic instruments to be located and secured by a single embodiment design, which may assume numerous possible configurations and orientations. In particular, the endoscopic visual lens, known in the art to be located off the centerline axis of the endoscope instrument, may be purposefully rotated and aligned with features of the invention intended to enhance and expand the visual field of view compared to prior art. This adaptive feature enables a wide range of devices, instrument guides, medicaments, delivery apparatus and the like to be integrated into the attachments of the invention, and thereby to be mounted, controlled, positioned and delivered using a single size embodiment device, thereby creating an endoscopic instrument with multifunctional capability and a wide angle field of view. A system for accomplishing this is described and claimed herein.